Air-conditioning system

ABSTRACT

According to one embodiment, an air conditioning system includes a compressor, a condenser, an expansion valve, a switching valve, an evaporator, a pump, a radiator, and a heat storage unit. The switching valve performs switching so that a first heat medium flows through either a first flow path or a second flow path. The pump supplies a second heat medium to the heat source. The heat storage unit has a heat storage material. The heat storage unit has a first heat exchange region in which heat is exchanged between the first heat medium flowing through the first flow path and the heat storage material. The heat storage unit has a second heat exchange region which is provided upstream of the radiator and in which heat is exchanged between the second heat medium supplied to the heat source and the heat storage material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2011-210318, filed on Sep. 27,2011; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to an air-conditioningsystem.

BACKGROUND

To cool a heating element such as a fuel cell mounted on a vehicle,there exists a cooling system which utilizes, as a heat sink, a heatmedium used for indoor cooling by an air conditioning system.

For example, there is proposed a cooling system which utilizes, as aheat sink, a heat medium used for indoor cooling to cool a heatingelement mounted on a vehicle via a heat exchanger, in which anevaporator for indoor cooling by an air conditioning system and the heatexchanger provided with a heat storage material are connected inparallel via a switching valve.

Here, in an air conditioning system, there may be a case where indoorheating is required in addition to indoor cooling. In this case,frosting of the evaporator for indoor heating in a cold district maycause decrease of heating efficiency, damage of the evaporator or thelike.

However, in the above-mentioned air conditioning system, using the heatof a heating element such as a fuel cell to remove the attached frosthas not been considered. Therefore it becomes necessary to use a heateror the like to remove the frost, which may increase power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an air conditioning systemaccording to a first embodiment.

FIG. 2A is a schematic cross-sectional view illustrating the heatstorage unit and FIG. 2B is a cross-sectional view taken along the linebetween the arrows A-A′ in FIG. 2A.

FIG. 3 is a schematic graph illustrating a temporal change in the amountof heat of the second heat medium recovered from the heat source 31(amount of heat recovered) when the vehicle is running.

FIG. 4A is a schematic cross-sectional view illustrating the heatstorage unit and FIG. 4B is a cross-sectional view taken along the linebetween the arrows B-B′ in FIG. 4A.

FIG. 5 is a flowchart illustrating an operation method of the coolingside circuit 10 a.

FIG. 6 is a block diagram illustrating an air conditioning systemaccording to a second embodiment.

FIG. 7 is a flowchart illustrating an operation method in the heatingside circuit 10 c.

FIG. 8 is a block diagram illustrating an air conditioning systemaccording to a third embodiment.

FIG. 9A is a schematic cross-sectional view illustrating the heatstorage unit and FIG. 9B is a cross-sectional view taken along the linebetween the arrows C-C′ in FIG. 9A.

FIG. 10 is a flowchart illustrating an operation method in the heatingside circuit 10 d.

DETAILED DESCRIPTION

In general, according to one embodiment, an air conditioning systemincludes a compressor, a condenser, an expansion valve, a switchingvalve, an evaporator, a pump, a radiator, and a heat storage unit. Thecompressor compresses a first heat medium taken therein. The compressordischarges the first heat medium. The condenser is provided on adischarge side of the compressor. The expansion valve is provided on theoutflow side of the condenser. The switching valve which is provided onthe outflow side of the expansion valve and which performs switching sothat the first heat medium flows through either a first flow path or asecond flow path. The evaporator is provided downstream of confluenceposition of the first flow path and the second flow path, on the intakeside of the compressor. The pump supplies a second heat medium to theheat source. The radiator releases heat of the second heat mediumsupplied to the heat source. The heat storage unit has a heat storagematerial. The heat storage unit has a first heat exchange region inwhich heat is exchanged between the first heat medium flowing throughthe first flow path and the heat storage material. The heat storage unithas a second heat exchange region which is provided upstream of theradiator and in which heat is exchanged between the second heat mediumsupplied to the heat source and the heat storage material.

Embodiments of the invention will now be described with reference to thedrawings. In the specification and the drawings of the application,components similar to those described in regard to a drawingthereinabove are marked with like reference numerals, and a detaileddescription is omitted as appropriate.

In the following, an air conditioning system installed in an ElectricVehicle (EV) or a fuel cell car (FCV) will be described as an example.

In addition, while there is a case where the state of a first heatmedium is liquid, gas, or gas-liquid two-phase state, it may also besimply referred to as the first heat medium.

In addition, while there is a case where the state of a second heatmedium is liquid or gas-liquid two-phase state, it may also be simplyreferred to as the second heat medium.

First Embodiment

FIG. 1 is a block diagram illustrating an air conditioning systemaccording to a first embodiment.

As shown in FIG. 1, an air conditioning system 1 is provided with a heatpump circuit 10 and a heat recovery circuit 30.

The heat pump circuit 10 is provided with a cooling side circuit 10 aand a heating side circuit 10 b. The cooling side circuit 10 a lowersthe temperature of the air used for cooling inside the vehicle byabsorbing heat from the air supplied into the vehicle.

The heating side circuit 10 b raises the temperature of the air used forheating inside the vehicle by causing the air supplied into the vehicleto absorb heat.

First, the cooling side circuit 10 a will be illustrated. The coolingside circuit 10 a is provided with a compressor 11, a switching valve14, a condenser 12, an expansion valve 15, an evaporator 17, and apiping 22.

The intake side of the compressor 11 has both the outflow side of theevaporator 17 and the outflow side of an evaporator 18 provided in theheating side circuit 10 b connected thereto. The discharge side of thecompressor 11 has the inflow side of the switching valve 14 connectedthereto.

The compressor 11 compresses gas of the first heat medium supplied fromthe evaporator 17 and the evaporator 18. The compressor 11 can beconfigured to compress, for example, gas of the first heat medium takenin from the intake side to thereby generate high-temperature,high-pressure gas of the first heat medium, and discharge the generatedhigh-temperature and high-pressure gas of the first heat medium from thedischarge side.

The outflow side of the switching valve 14 has both the inflow side ofthe condenser 12 and the inflow side of a condenser 13 provided in theheating side circuit 10 b connected thereto.

The switching valve 14 switches the supply of the gas of thehigh-temperature and high-pressure first heat medium discharged from thecompressor 11, to either of the condenser 12 and the condenser 13. Theswitching valve 14 can be set as, for example, a three-way valve whichis provided with an electromagnetic coil and which switches the flowpath by supplying or terminating power to the electromagnetic coil orthe like.

The outflow side of the condenser 12 has the inflow side of theexpansion valve 15 connected thereto.

The condenser 12, having a blower fan (not shown), for example, can beconfigured to exchange heat between the air blown by the blower fan fromoutside the vehicle, and the high-temperature and high-pressure gas ofthe first heat medium discharged from the compressor 11. Thehigh-temperature and high-pressure gas of the first heat mediumdischarged from the compressor 11 is condensed by having its heatabsorbed by the air blown from outside the vehicle.

The outflow side of the expansion valve 15 has the inflow side of theevaporator 17 connected thereto.

The expansion valve 15 adiabatically expands the first heat mediumcondensed by the condenser 12 to thereby reduce its pressure, andgasifies a part of the first heat medium to thereby be turned into thefirst heat medium in a gas-liquid two-phase state.

The outflow side of the evaporator 17 has the intake side of thecompressor 11 connected thereto.

The evaporator 17 is provided inside a ventilation duct 21 havingprovided therein a blower fan 21 a for supplying air into the vehicle.The evaporator 17 exchanges heat between the air blown by the blower fan21 a and the first heat medium in a gas-liquid two-phase state which hasflown in from the expansion valve 15. The first heat medium in agas-liquid two-phase state turns into gas of the first heat medium byabsorbing heat from the blown air and is supplied to the compressor 11.In addition, the air having its heat absorbed by the evaporator 17 issupplied into the vehicle to be used for cooling inside the vehicle.

The piping 22 connects the components provided in the cooling sidecircuit 10 a and serves as a flow path of the first heat medium.

Next, the heating side circuit 10 b will be described.

The heating side circuit 10 b is provided with the compressor 11, theswitching valve 14, the condenser 13, an expansion valve 16, a heatstorage unit 19, the evaporator 18, and pipings 22 a to 23 c.

The condenser 13 is provided on the discharge side of the compressor 11.The outflow side of the condenser 13 has the inflow side of theexpansion valve 16 connected thereto via the piping 23 a.

The condenser 13 is provided inside the above-mentioned ventilation duct21.

The condenser 13 may be configured to exchange heat between the airblown by the blower fan 21 a and the high-temperature and high-pressuregas of the first heat medium discharged from the compressor 11 via theswitching valve 14. The high-temperature and high-pressure gas of thefirst heat medium discharged from the compressor 11 is condensed byhaving its heat absorbed by the blown air. In addition, the air blown tothe condenser 13 is heated by absorbing heat from the gas of the firstheat medium, and the heated air is supplied into the vehicle to be usedfor heating inside the vehicle.

The expansion valve 16 is provided on the outflow side of the condenser13. The outflow side of the expansion valve 16 has the inflow side ofthe evaporator 18 connected thereto via the piping 23 c.

The expansion valve 16 adiabatically expands the first heat mediumcondensed by the condenser 13, to reduce its pressure, and gasifies apart of the first heat medium to thereby be turned into the first heatmedium in a gas-liquid two-phase state.

The outflow side of the evaporator 18 has the intake side of thecompressor 11 connected thereto via the piping 23 b. The evaporator 18is provided with, for example, a blower fan (not shown), and can beconfigured to exchange heat between the air blown by the blower fan fromoutside the vehicle and the first heat medium in a gas-liquid two-phasestate which has flown in from the expansion valve 16 via the heatstorage unit 19. The first heat medium in a gas-liquid two-phase stateturns into gas of the first heat medium by absorbing heat from the blownair and is supplied to the compressor 11.

The heat storage unit 19 is provided between the expansion valve 16 andthe evaporator 18.

A heat storage material 24 is provided inside the heat storage unit 19and stores the heat supplied from the heat recovery circuit 30. Inaddition, the heat storage unit 19 supplies the heat stored in the heatstorage material 24 to the first heat medium in a gas-liquid two-phasestate, which is supplied to the evaporator 18 from the expansion valve16. Supplying, to the evaporator 18, the first heat medium in agas-liquid two-phase state which has been heated by supplying heatthereto can raise the temperature of the evaporator 18. Accordingly,frost can be prevented from sticking to the evaporator 18 in cold areas.In addition, even when there is frost sticking to the evaporator 18 atthe time of start-up, the frost can be removed. As a result, decrease ofheating efficiency, damage of the evaporator, or the like can besuppressed.

Details about the heat storage unit 19 will be described below.

In addition, the first heat medium used for the cooling side circuit 10a and the heating side circuit 10 b can be, for example, ammonia,hydrofluorocarbon (HFC), hydrochlorofluoro carbon (HCFC), or the like.

Next, the heat recovery circuit 30 will be illustrated.

The heat recovery circuit 30 is provided with a pump 34, a radiator 33,and a piping 32.

The heat recovery circuit 30 cools a heat source 31 by absorbing heat ofthe heat source 31, and stores heat in the heat storage unit 19 bysupplying the absorbed heat to the heat storage unit 19.

The intake side of pump 34 has the outflow side of the radiator 33connected thereto. The heat source 31 is connected to the discharge sideof the pump 34.

The pump 34 supplies the second heat medium to the heat source 31. Inaddition, the pump 34 circulates the second heat medium among the heatsource 31, the heat storage unit 19, and the radiator 33.

The radiator 33 releases the heat of the second heat medium supplied tothe heat source 31. The radiator 33 is provided with, for example, ablower fan (not shown), and can be configured to exchange heat betweenthe air blown by the blower fan from outside the vehicle and the secondheat medium which has flown in from the heat source 31 via the heatstorage unit 19.

The radiator 33, for example, can be a radiator provided in an electricvehicle or a fuel-cell vehicle.

The second heat medium which has absorbed heat from the heat source 31causes its heat to be absorbed by the heat storage unit 19, and furthercauses its heat to be absorbed by the air from outside the vehicle,blown by the radiator 33. Subsequently, the second heat medium which hasbeen cooled by causing its heat to be absorbed is supplied to the heatsource 31 and used for cooling the heat source 31.

The piping 32 connects the pump 34, the radiator 33, the heat storageunit 19, and the heat source 31, and serves as a flow path of the secondheat medium.

The heat source 31 can be configured to generate heat for the motor,inverter, fuel-cell stack or the like provided in a electric vehicle ora fuel-cell vehicle, for example.

The second heat medium can be water, for example.

Next, the heat storage unit 19 will be further illustrated.

FIG. 2 is a schematic view illustrating the heat storage unit. Here,FIG. 2A is a schematic cross-sectional view illustrating the heatstorage unit and FIG. 2B is a cross-sectional view taken along the linebetween the arrows A-A′ in FIG. 2A.

FIG. 3 is a schematic graph illustrating a temporal change in the amountof heat of the second heat medium recovered from the heat source 31(amount of heat recovered) when the vehicle is running.

FIG. 3 illustrates a case of a vehicle running at the 10-15 drivingmode.

In addition, the temperature at the intake port and the outlet port ofthe second heat medium in the heat source 31 was measured by anexperiment, and thus the amount of heat recovered was tried to becalculated from the difference between the temperatures at the outletport and the intake port of the second heat medium.

As can be seen from FIG. 3, the amount of heat generated in the heatsource 31 varies with run time.

Here, the amount of heat exchange between the heat storage material 24provided in the heat storage unit 19 and the first heat medium flowinginside the flow path 28 (heat absorption by the first heat medium fromthe heat storage material 24) becomes larger as the difference oftemperature is larger between the heat storage material 24 and the firstheat medium. In this case, as shown in FIG. 3, since the amount of heatgenerated from the heat source 31 varies depending on the runningcondition of the electric vehicle or fuel-cell vehicle, the temperatureof the second heat medium flowing inside the flow path 29 also varies.

When, not via the heat storage material 24, direct heat exchange isperformed between the first heat medium flowing inside the flow path 28and the second heat medium flowing inside the flow path 29, it becomesdifficult to supply heat to the first heat medium from the second heatmedium when the amount of heat of the second heat medium is close to 0.

In contrast, when the temperature of the evaporator 18 (T_(ev2)) is notless than a predetermined lower limit (T_(min)), i.e, for example, it isnot necessary to remove the frost sticking to the evaporator 18, theheat absorbed by the second heat medium from the heat source 31 during aperiod during which heat exchange is not necessary is wasted because itis released from the radiator 33 to the outside.

Therefore, in the embodiment, the heat storage unit 19 having the heatstorage material 24 is provided so that the heat generated in the heatsource 31 during a period during which heat exchange is not necessarycan be stored.

Providing the heat storage unit 19 causes the temperature of theevaporator 18 (T_(ev2)) to be less than a predetermined lower limit(T_(min)), and thus heat can be supplied from the heat storage material24 to the first heat medium when it is necessary to cause the first heatmedium to absorb the heat.

In addition, as described below, a latent heat storage material(phase-change heat storage material) is used as the heat storagematerial 24, or a heat exchange region 26 (corresponding to an exampleof the first heat exchange region) in which the first heat medium andthe heat storage material 24 exchange heat, and a heat exchange region27 (corresponding to an example of the second heat exchange region) inwhich the second heat medium and the heat storage material 24 exchangeheat are configured to be adjacent. Accordingly, since variation of thetemperature of the second heat medium, if any, can be relaxed, thetemperature of the heat storage material 24 can be maintainedsubstantially constant. Therefore, the amount of heat exchanged at thetime of heat exchange between the heat storage material 24 and the firstheat medium can be maintained substantially constant, and thus itbecomes possible to efficiently remove the frost sticking to theevaporator 18.

When the amount of heat stored in the heat storage material 24 is lessthan the amount of heat which is necessary to be supplied to the firstheat medium, a heating unit 191 (for example, a heater or the like)which heats the heat storage material 24 can be provided. In this case,heat from heating unit 191 is absorbed by the heat storage material 24,and absorbed by the first heat medium in the heat exchange region 26.

Next, returning to FIG. 2, the heat storage unit 19 will be furtherdescribed.

The heat storage unit 19 is provided with a casing 25, the flow path 28,the flow path 29, the heat storage material 24, and a nucleation unit300.

Furthermore, the heat storage unit 19 has the heat exchange region 26which exchanges heat between the first heat medium flowing through theflow path 28 and the heat storage material 24, and a heat exchangeregion 27 which is provided upstream of the radiator 33 and whichexchanges heat between the second heat medium supplied to the heatsource 31 and the heat storage material 24.

The heat exchange region 27 is provided closer to the center of the heatstorage unit 19 than the heat exchange region 26.

The casing 25 has the flow path 28, the flow path 29, the heat storagematerial 24, and nucleation unit 300 housed therein.

The inner wall of the casing 25 has a concave portion 301 providedthereon. The concave portion 301 will be described below.

The flow path 28 is formed of a tubular member. The flow path 28 has anannulus part 28 a and a joint 28 b connected to the annulus part 28 a.The annulus part 28 a is provided on the heat exchange region 26 locatedon the inner wall side of the casing 25. The annulus part 28 a isprovided in the vicinity of one end of the casing 25. The piping 23 c isconnected to an end on the side opposite to the side connected to theannulus part 28 a of the joint 28 b. Accordingly, the first heat mediumcan flow inside the flow path 28. In addition, a plurality of theannulus part 28 a can be provided.

The flow path 29 is formed of a tubular member. The flow path 29 has aspiral part 29 a and joints 29 b provided at both ends of the spiralpart 29 a.

The spiral part 29 a is provided in the heat exchange region 27 providedinside the heat exchange region 26. The joint 29 b has the piping 32connected thereto. Accordingly, the second heat medium can flow insidethe flow path 29.

In the heat storage unit 19 according to the embodiment, the flow path29 through which the second heat medium having a high temperature flowsis provided on the center side of the heat storage unit 19, and the flowpath 28 through which the first heat medium having a temperature lowerthan the temperature of the second heat medium flows is provided on theinner wall side of the heat storage unit 19.

In this case, on the assumption that the flow path 29 through which thehigh-temperature second heat medium flows is provided on the inner wallside of the heat storage unit 19, heat dissipation becomes larger. Incontrast to this, on the assumption that the flow path 29 through whichthe high-temperature second heat medium flows is provided on the centerside of the heat storage unit 19, the distance to the surface of thecasing 25 can be increased, and thus heat dissipation can be suppressed.

In addition, the ability (heat output) required when releasing heat tothe first heat medium is generally higher than the ability required whenstoring the heat from the second heat medium. Therefore, it is preferredto increase the amount of heat exchanged between the heat storagematerial 24 and the first heat medium, by making the length of the flowpath 28 through which the first heat medium flows longer. In this case,since the flow path 28 through which the first heat medium flows isprovided on the inner wall side of the casing 25, it becomes easy tomake the length of the flow path 28 longer.

Accordingly, assuming the above-mentioned arrangement of the flow path28 and the flow path 29, the efficiency of heat exchange can beimproved.

For the heat storage material 24, a material having a heat-storingdensity higher than the second heat medium can be used. The heat storagematerial 24 can be, for example, a latent heat storage material. As thelatent heat storage material, an inorganic hydrate material (sodiumacetate hydrate or sodium sulphate hydrate), an organic material(paraffin or erythritol), for example, can be exemplified. The heatstorage material 24 liquefies when the temperature is higher than themelting point of the material to be formed, and solidifies when thetemperature is lower than the melting point. In this case, a largeamount of heat is absorbed or released at the melting point(phase-change temperature) at which phase-change occurs.

In addition, some latent heat storage materials may be capable ofsupercooling. A latent heat storage material capable of supercoolingmaintains a liquid state without solidification even when it thetemperature is lower than the melting point. Furthermore, an externalstimulation (for example, mechanical nucleation, electric nucleation,etc.) or addition of a crystalline nucleus can release supercooling andcause solidification to occur. In this case, heat can be released fromthe latent heat storage material by releasing supercooling and causingsolidification to occur.

As a latent heat storage material capable of supercooling, sodiumacetate trihydrate or the like can be exemplified. On the assumptionthat a latent heat storage material capable of supercooling is used,supercooling can be stably maintained also in a subfreezing environment.Moreover, on the assumption that a latent heat storage material capableof supercooling is used, heat can be stored for a long time. Therefore,even when heating is started from a state in which the latent heatstorage material is left in a low temperature environment in winter fora long time, frost sticking to the evaporator 18 can be removed. Inaddition, on the assumption that a latent heat storage material capableof supercooling is used, it becomes possible to release heat at adesired time by external stimulation or the like. Accordingly, itbecomes possible, for example, to remove the frost sticking to theevaporator 18 at a fixed time interval, or remove the frost sticking tothe evaporator 18 when needed.

Inside the casing 25 having housed the flow path 28, the flow path 29,and the nucleation unit 300 is filled with the heat storage material 24.In this case, the flow path 28 is in contact with the heat storagematerial 24 located in the heat exchange region 26. The flow path 29contacts the heat storage material 24 located in the heat exchangeregion 27. Therefore, the flow path 28 and the flow path 29 do notdirectly contact each other.

The second heat medium having absorbed heat by passing through the heatsource 31 when the heat source 31 is generating heat, exchanges heatwith the heat storage material 24 in the heat exchange region 27 of theheat storage unit 19, and the heat storage material 24 absorbs heat(stores heat). In this case, the amount of heat that can be absorbedfrom the second heat medium by the heat storage material 24 decreaseswhen the melting point of the heat storage material 24 is high. Incontrast, the amount of heat that can be absorbed from the heat storagematerial 24 by the first heat medium increases.

In this case, after having preliminarily determined, from the relationbetween the temperature of the second heat medium and the temperature ofthe first heat medium, the amount of heat to be absorbed by the heatstorage material 24 from the second heat medium, a material of the heatstorage material 24 having a melting point satisfying the amount of heatcan be selected.

In addition, when heat exceeding the amount that can be stored in latentheat is supplied from the second heat medium to the heat storagematerial 24, the temperature of the heat storage material 24 riseshigher than the melting point, and heat is stored by sensible heat.

In addition, when the temperature of the heat storage material 24 hasrisen higher than a predetermined value, the temperature of the heatstorage material 24 can be prevented from becoming higher than thepredetermined value by cooling the second heat medium by the radiator 33provided in the heat recovery circuit 30.

The nucleation unit 300 is provided inside the heat storage unit 19 andcauses the heat storage material 24 to nucleate. The nucleation unit 300can be provided in a case where a latent heat storage material capableof supercooling is used as the heat storage material 24. As thenucleation unit 300, for example, an electrode which applies voltage tothe heat storage material 24, or the like can be exemplified. When heatis desired to be absorbed from the heat storage material 24 into thefirst heat medium, i.e., for example, when the frost sticking to theevaporator 18 is removed, the nucleation unit 300 may apply a voltage tothe heat storage material 24. When a voltage is applied to the heatstorage material 24 by the nucleation unit 300, the heat storagematerial 24 is nucleated with the heat storage material 24 in thevicinity of the nucleation unit 300 being the starting point. Nucleationof the heat storage material 24 releases supercooling, and thus heat isreleased from the heat storage material 24.

Providing the nucleation unit 300 also makes it possible to release heatfrom the heat storage material 24 at a desired time. Accordingly, itbecomes possible, for example, to remove the frost sticking to theevaporator 18 at a fixed time interval, or remove the frost sticking tothe evaporator 18 when needed.

The inner wall of the casing 25 is provided with a concave portion 301,and the concave portion 301 is provided above the nucleation unit 300.For example, the nucleation unit 300 is provided downward in the gravitydirection, inside the heat storage unit 19. In addition, the concaveportion 301 is provided upward in the gravity direction, on the innerwall of the casing 25. When the heat storage material 24 is nucleated,the heat storage material 24 is subject to phase change from liquid tosolid, and on this occasion, change of volume (density) occurs. In theembodiment, nucleation is caused from the lower side of the heat storageunit 19, by providing the nucleation unit 300 downward in the gravitydirection. Then, the volume change having occurred by causing the heatstorage unit 19 to nucleate from the lower side is absorbed by theconcave portion 301 provided upward in the gravity direction of the heatstorage unit 19.

FIG. 4 is a schematic view illustrating the heat storage unit accordingto another embodiment. Here, FIG. 4A is a schematic cross-sectional viewillustrating the heat storage unit and FIG. 4B is a cross-sectional viewtaken along the line between the arrows B-B′ in FIG. 4A.

As shown in FIG. 4, the heat storage unit 19 a is provided with thecasing 25, a flow path 128, the flow path 29, the heat storage material24, and the nucleation unit 300.

The flow path 128 is formed of a tubular member. The flow path 128 has aspiral part 128 a and joints 128 b provided at both ends of the spiralpart 128 a.

The spiral part 128 a is provided in the heat exchange region 26. Thejoint 128 b has the piping 32 connected thereto. Accordingly, the firstheat medium can flow inside the flow path 128.

The heat storage unit 19 a according to the embodiment can obtain afunction and effect similar to the above-mentioned heat storage unit 19.In addition, the spiral part 128 a being spiral-shaped can makecirculation of the first heat medium smooth.

The form of the flow path provided in the heat storage unit is notlimited to one which has been illustrated. For example, the flow pathprovided in the heat storage unit can be formed of a tubular member in ameandering manner.

Next, an operation method of the air conditioning system 1 will beillustrated.

(Cooling Operation)

FIG. 5 is a flowchart illustrating an operation method of the coolingside circuit 10 a. When instructed to perform cooling inside the vehicle(step S01), the outflow side of the compressor 11 and the piping 22 areconnected (step S02) by performing switching by the switching valve 14.Subsequently, by driving the compressor 11, the first heat medium iscaused to circulate in the cooling side circuit 10 a (step S03).

In this case, after having released heat to the outside of the vehiclein the condenser 12, the first heat medium which has been compressed inthe compressor 11 is expanded in the expansion valve 15 and draws heatfrom the air in the evaporator 17. When the blower fan 21 a operates,the air having heat drawn in the evaporator 17 is supplied into thevehicle. In this manner, cooling operation is performed.

(Heating Operation)

When instructed to perform heating, the outflow side of the compressor11 and the piping 23 a are connected by performing switching by theswitching valve 14. Subsequently, by driving the compressor 11, thefirst heat medium is caused to circulate in the heating side circuit 10b.

In this case, the first heat medium which has been compressed in thecompressor 11 is condensed in the condenser 13, and causes the airsupplied by the blower fan 21 a to absorb the condensation heat.Subsequently, the first heat medium is expanded in the expansion valve16, circulates in the heating side circuit 10 b by passing through theheat storage unit 19 and the evaporator 18, and returning to thecompressor 11 again.

The heat storage unit 19 is filled with the heat storage material 24having a melting point higher than the temperature of the inflowingfirst heat medium.

Since a large amount of heat is generated in the heat source 31, theheat can be recovered in the heat recovery circuit 30. Then, by causingthe first heat medium to absorb the recovered heat via the heat storageunit 19, a part of the first heat medium can be vaporized. Accordingly,in the heat storage unit 19, by vaporizing a part of the first heatmedium, evaporation in the evaporator 18 can be assisted. As a result,it becomes possible to reduce power consumption in the evaporator 18.

In addition, it is also possible to release heat from the heat storagematerial 24 by the above-mentioned nucleation unit 300 at a desiredtime. Accordingly, it is possible, for example, to remove the froststicking to the evaporator 18 at a fixed time interval, or remove thefrost sticking to the evaporator 18 when needed.

In contrast, in the heat recovery circuit 30, the heat generated by theheat source 31 is absorbed by the heat storage unit 19, and thus theamount of heat to be released by the radiator 33 is reduced. Therefore,it becomes possible to reduce power consumption for releasing heat inthe radiator 33.

Since functions of respective components for cooling and heatingoperations are similar to that mentioned above, detailed descriptionthereof is omitted.

Second Embodiment

FIG. 6 is a block diagram illustrating an air conditioning systemaccording to a second embodiment.

As shown in FIG. 6, an air conditioning system 50 is provided with aheat pump circuit 51 and the heat recovery circuit 30.

The heat pump circuit 51 is provided with the cooling side circuit 10 aand a heating side circuit 10 c. The cooling side circuit 10 a lowersthe temperature of the air used for cooling inside the vehicle byabsorbing heat from the air supplied into the vehicle.

The heating side circuit 10 c raises the temperature of the air used forheating inside the vehicle by causing the air supplied into the vehicleto absorb heat.

The heating side circuit 10 c is provided with the compressor 11, theswitching valve 14, the condenser 13, the expansion valve 16, aswitching valve 20, the heat storage unit 19, the evaporator 18, thepipings 23 a, 23 b, 23 c (corresponding to an example of the first flowpath), and 23 d (corresponding to an example of the second flow path),and a temperature measuring unit 18 a (corresponding to an example ofthe first temperature measuring unit).

One outflow side of the switching valve 20 has the inflow side of theheat storage unit 19 connected thereto via the piping 23 c. The otheroutflow side of the switching valve 20 has the inflow side of theevaporator 18 connected thereto via the piping 23 d. The inflow side ofthe switching valve 20 has the outflow side of the expansion valve 16connected thereto via the piping 23 a.

The switching valve 20 is provided on the outflow side of the expansionvalve 16, and switches between the piping 23 c and the piping 23 d sothat the first heat medium in a gas-liquid two-phase state which hasflown out from the expansion valve 16 flows into any of the piping 23 cand the piping 23 d. The switching valve 20 can be, for example, athree-way valve which is provided with an electromagnetic coil and whichswitches the flow path by supplying or terminating power to theelectromagnetic coil. However, the switching valve 20 is not limited toa three-way valve, and may be, for example, an on-off valve provided toboth the piping 23 c and the piping 23 d.

The evaporator 18 is provided downstream of the confluence point of thepiping 23 c and the piping 23 d, on the intake side of the compressor11.

The temperature measuring unit 18 a measures the temperature of theevaporator 18. The switching valve 20 performs switching, based on thetemperature of the evaporator 18 measured by the temperature measuringunit 18 a, so that the first heat medium flows through either the piping23 c or the piping 23 d.

In the embodiment, the heat storage unit 19 can be selectively used byswitching the flow of the first heat medium by the switching valve 20.Therefore, when the above-mentioned nucleation unit 300 is not provided,i.e., for example, even when latent heat storage material is not used asthe heat storage material 24, it is possible to cause the first heatmedium to absorb heat in the heat storage unit 19 at a desired time.Accordingly, it becomes possible, for example, to remove the froststicking to the evaporator 18 at a fixed interval, or to remove thefrost sticking to the evaporator 18 when needed.

Controlling the switching by the switching valve 20 based on themeasurement result by the temperature measuring unit 18 a will bedescribed below.

Operation by the driver or the like also makes it possible to performswitching by the switching valve 20.

Next, an operation method of the air conditioning system 50 will beillustrated.

Since the cooling operation may be configured to be similar to theoperation method in the cooling side circuit 10 a illustrated in FIG. 5,description thereof is omitted.

(Heating Operation)

In the following, as an example, a case of controlling the switching bythe switching valve 20 based on the measurement result by thetemperature measuring unit 18 a will be illustrated.

FIG. 7 is a flowchart illustrating an operation method in the heatingside circuit 10 c.

When instructed to perform heating inside the vehicle (step S11), theinflow side of the condenser 13 and the outflow side of the compressor11 are connected by performing switching by the switching valve 14 (stepS12).

Next, the temperature of the evaporator 18 (T_(ev2)) is measured by thetemperature measuring unit 18 a (step S13). The measured temperature ofthe evaporator 18 can be converted into the temperature of the firstheat medium flowing inside the evaporator 18. In this case, bypreliminarily obtaining the relation between the temperature of theevaporator 18 and the temperature of the first heat medium flowinginside the evaporator 18 from an experiment or the like, temperatureconversion can be performed based on the obtained relation.

When the measured temperature of the evaporator 18 is higher than apredetermined value, the switching valve 20 performs switching so thatthe first heat medium flows through the piping 23 d.

For example, when the temperature of the evaporator 18 (T_(ev2)) is notless than the predetermined lower limit (T_(min)), inflow of the firstheat medium into the heat storage unit 19 side is blocked by theswitching valve 20 (steps S14 and S15 a).

Subsequently, by driving the compressor 11, the first heat medium iscaused to circulate through a predetermined path in the heating sidecircuit 10 c (step S16). That is, the first heat medium is caused tocirculate in the compressor 11, the switching valve 14, the condenser13, the expansion valve 16, the switching valve 20, and the evaporator18.

In this case, the air blown to the condenser 13 is heated by absorbingheat from the gas of the first heat medium, and the heated air issupplied into the vehicle to be used for heating inside the vehicle.

In addition, since the heat stored in the heat storage material 24 inthe heat storage unit 19 is not absorbed by the first heat medium, theheat from the heat recovery circuit 30 can be stored in the heat storagematerial 24.

In contrast, when the measured temperature of the evaporator 18 is lowerthan the predetermined value, switching is performed so that the firstheat medium flows through the piping 23 c.

For example, when the temperature of the evaporator 18 (T_(ev2)) islower than the predetermined lower limit (T_(min)), inflow of the firstheat medium into the heat storage unit 19 side is carried out by theswitching valve 20 (steps S14 and S15 b).

Subsequently, by driving the compressor 11, the first heat medium iscaused to circulate through a predetermined path in the heating sidecircuit 10 c (step S16). That is, the first heat medium is caused tocirculate in the compressor 11, the switching valve 14, the condenser13, the expansion valve 16, the switching valve 20, the heat storageunit 19, and the evaporator 18.

Also in this case, the air blown to the condenser 13 is heated byabsorbing heat from the gas of the first heat medium, and the heated airis supplied into the vehicle to be used for heating inside the vehicle.

Here, under a low-temperature and high-humidity environment such as incold areas, freezing of moisture in the air may cause frost to stick tothe evaporator 18. Since frost sticking to the evaporator 18 decreasesthe heat exchange efficiency (ability of vaporizing the first heatmedium) in the evaporator 18, heating performance may significantlydegrade.

Therefore, the embodiment is configured to determine whether or notfrost is sticking by measuring the temperature of the evaporator 18(T_(ev2)) by the temperature measuring unit 18 a provided in theevaporator 18.

For example, when the temperature of the evaporator 18 (T_(ev2)) islower than the predetermined lower limit (T_(min)), it is determinedthat frost is sticking, and the first heat medium is caused to flow intothe heat storage unit 19 side. As described above, the first heat mediumwhich has flown into the flow path 28 of the heat storage unit 19absorbs heat from the heat storage material 24. Therefore, load on theevaporator 18 is reduced, and thus the amount of sticking frost can bereduced. In addition, a heater may be provided in the evaporator 18.

Furthermore, a latent heat storage material capable of supercooling isused as the heat storage material 24, and when the latent heat storagematerial is in a supercooled state, supercooling is released by thenucleation unit 300 after it has been determined that the temperature ofthe evaporator 18 (T_(ev2)) is lower than the predetermined lower limit(T_(min)). Accordingly, even when the period from storing heat in theheat storage material 24 to releasing the heat is long, heat at themelting point can be released from the heat storage material 24, andthus the first heat medium can absorb sufficient heat.

Third Embodiment

FIG. 8 is a block diagram illustrating an air conditioning systemaccording to a third embodiment.

As shown in FIG. 8, the air conditioning system 100 is provided with theheat pump circuit 101 and the heat recovery circuit 30.

The heat pump circuit 101 is provided with the cooling side circuit 10 aand the heating side circuit 10 d.

The cooling side circuit 10 a lowers the temperature of the air used forcooling inside the vehicle drop by absorbing heat from the air suppliedinto the vehicle.

The heating side circuit 10 d raises the temperature of the air used forheating inside the vehicle by causing the air supplied into the vehicleto absorb heat.

The heating side circuit 10 d is provided with the compressor 11, theswitching valve 14, the condenser 13, the expansion valve 16, theswitching valve 20, the heat storage unit 190, the evaporator 18, thepipings 22 a to 23 d, the temperature measuring unit 18 a, and atemperature measuring unit 11 a (corresponding to an example of thesecond temperature measuring unit).

One outflow side of the switching valve 20 has the inflow side of theheat storage unit 190 connected thereto via the piping 23 c. The otheroutflow side of the switching valve 20 had the inflow side of theevaporator 18 connected thereto via the piping 23 d. The inflow side ofthe switching valve 20 has the outflow side of the expansion valve 16connected thereto via the piping 23 a.

The switching valve 20 switches the supply of the first heat medium in agas-liquid two-phase state, flown out from the expansion valve 16, toeither of the heat storage unit 190 and the evaporator 18.

The temperature measuring unit 11 a measures the temperature of thecompressor 11.

The switching valve 20 performs switching, based on the temperature ofthe compressor 11 measured by the temperature measuring unit 11 a, sothat the first heat medium flows through either the piping 23 c or thepiping 23 d. In addition, the switching valve 20 performs switching,based on the temperature of the compressor 11 measured by thetemperature measuring unit 11 a and the temperature of the evaporator 18measured by the temperature measuring unit 18 a, so that the first heatmedium flows through either the piping 23 c or the piping 23 d.

Also in the air conditioning system 100 according to the embodiment, theheat storage unit 190 can be selectively used by switching the flow ofthe first heat medium by the switching valve 20.

Controlling the switching by the switching valve 20 based on themeasurement result by the temperature measuring unit 11 a and thetemperature measuring unit 18 a will be described below.

Operation by the driver or the like also makes it possible to performswitching by the switching valve 20.

Next, the heat storage unit 190 will be further illustrated.

FIG. 9 is a schematic view illustrating the heat storage unit. FIG. 9Ais a schematic cross-sectional view illustrating the heat storage unitand FIG. 9B is a cross-sectional view taken along the line between thearrows C-C′ in FIG. 9A.

As shown in FIG. 9, the heat storage unit 190 is provided with thecasing 25, the flow path 128, a flow path 129, the heat storage material24, the nucleation unit 300, and the temperature measuring unit 11 a.

The flow path 129 is formed of a tubular member. The flow path 129 has aspiral part 129 a and joints 129 b provided at both ends of the spiralpart 129 a.

The spiral part 129 a is provided in the heat exchange region 27provided inside the heat exchange region 26. The joint 129 b has thepiping 32 connected thereto. Accordingly, the second heat medium canflow inside the flow path 129.

The compressor 11 is thermally connected to the heat storage unit 190.

With regard to that illustrated in FIG. 9, the compressor 11 is providedin a manner penetrating the center of the casing 25, and the heatstorage material 24 and the casing 25 contact the outer face of thecompressor 11. Then, the outer periphery side of the compressor 11inside the casing 25 becomes the heat exchange region 27.

Since the compressor 11 generates heat when the compressor 11 isoperated, the compressor 11 also serves as the heat source. Therefore,in the heat storage unit 190, heat generated from the compressor 11 canalso be stored in the heat storage material 24.

In this case, when the temperature of the heat storage material 24 islower than the temperature of the compressor 11, heat from thecompressor 11 is absorbed (stored), via the casing 25 or directly, inthe heat storage material 24. In contrast, when the temperature of theheat storage material 24 is higher than the temperature of thecompressor 11, heat from the heat storage material 24 will be absorbedby the compressor 11.

Next, an operation method of the air conditioning system 100 will beillustrated.

Since the cooling operation can be configured to be similar to theoperation method in the cooling side circuit 10 a illustrated in FIG. 5,description thereof is omitted.

(Heating Operation)

In the following, as an example, a case of controlling the switching bythe switching valve 20 based on the measurement result by thetemperature measuring unit 11 a and the temperature measuring unit 18 awill be illustrated.

FIG. 10 is a flowchart illustrating an operation method in the heatingside circuit 10 d.

When instructed to perform heating inside the vehicle (step S31), theinflow side of the condenser 13 and the outflow side of the compressor11 are connected by performing switching by the switching valve 14 (stepS32).

Next, the temperature of the compressor 11 (T_(comp)) is measured by thetemperature measuring unit 11 a (step S33).

When the measured temperature of the compressor 11 is lower than apredetermined value, the switching valve 20 performs switching so thatthe first heat medium flows through the piping 23 d.

For example, when the temperature of the compressor 11 (T_(comp)) islower than a predetermined lower limit (T_(comp) _(—) _(min)), inflow ofthe first heat medium into the heat storage unit 190 side is blocked bythe switching valve 20 (steps S34 and S37).

In this case, by driving the compressor 11 (step S39), the first heatmedium is caused to circulate through a predetermined path in theheating side circuit 10 d. That is, the first heat medium is caused tocirculate in the compressor 11, the switching valve 14, the condenser13, the expansion valve 16, the switching valve 20, and the evaporator18.

In this case, the air blown to the condenser 13 is heated by absorbingheat from the gas of the first heat medium, and the heated air issupplied into the vehicle to be used for heating inside the vehicle.

In addition, since the heat stored in the heat storage material 24 inthe heat storage unit 190 is not absorbed by the first heat medium, theheat from the heat recovery circuit 30 can be stored in the heat storagematerial 24.

In addition, a latent heat storage material capable of supercooling isused as the heat storage material 24 and, when the latent heat storagematerial is in a supercooled state, supercooling is released by thenucleation unit 300 after it has been determined that the temperature ofthe compressor 11 (T_(comp)) is lower than the predetermined lower limit(T_(comp) _(—) _(min)). Accordingly, the heat stored in the heat storagematerial 24 can be absorbed by the compressor 11.

When the temperature of the compressor 11 is low, there is a risk inwhich the heat may escape from the gas of the compressed,high-temperature first heat medium to the compressor 11, resulting in areduced heating performance.

Therefore, for example, when it is determined that the temperature ofthe compressor 11 (T_(comp)) is lower than the predetermined lower limit(T_(comp) _(—) _(min)), heat is provided from the heat storage tank 190to the compressor 11, and thus escape of heat from the compressor 11 issuppressed.

In contrast, for example, when the temperature of the compressor(T_(comp)) is not less than the predetermined lower limit (T_(comp) _(—)_(min)), the temperature of the evaporator 18 (T_(ev2)) is measured bythe temperature measuring unit 18 a (steps S34 and S35).

When, for example, the temperature of the evaporator 18 (T_(ev2)) is notless than the predetermined lower limit (T_(min)), inflow of the firstheat medium into the heat storage unit 190 side is blocked by theswitching valve 20 (steps S36 and S37).

In this case, by driving the compressor 11 (step S39), the first heatmedium is caused to circulate through a predetermined path in theheating side circuit 10 d. That is, the first heat medium is caused tocirculate in the compressor 11, the switching valve 14, the condenser13, the expansion valve 16, the switching valve 20, and the evaporator18.

For example, when the temperature of the compressor 11 (T_(comp)) is notless than the predetermined lower limit (T_(comp) _(—) _(min)) and thetemperature of the evaporator 18 (T_(ev2)) is not less than thepredetermined lower limit (T_(min)), heat from the compressor 11 andheat from the heat recovery circuit 30 are stored in the heat storagematerial 24. In this case, since inflow of the first heat medium intothe heat storage unit 190 side is blocked by the switching valve 20, theheat stored in the heat storage material 24 is not absorbed by the firstheat medium.

In contrast to this, for example, when the temperature of the evaporator18 (T_(ev2)) is lower than the predetermined lower limit (T_(min)),inflow of the first heat medium into the heat storage unit 190 side iscaused by the switching valve 20 (steps S36 and S38).

In this case, by driving the compressor 11 (step S39), the first heatmedium is caused to circulate through a predetermined path in theheating side circuit 10 d. That is, the first heat medium is caused tocirculate in the compressor 11, the switching valve 14, the condenser13, the expansion valve 16, the switching valve 20, the heat storageunit 190, and the evaporator 18.

For example, when the temperature of the compressor 11 (T_(comp)) is notless than the predetermined lower limit (T_(comp) _(—) _(min)) and thetemperature of the evaporator 18 (T_(ev2)) is lower than thepredetermined lower limit (T_(min)), inflow of the first heat mediuminto the heat storage unit 190 side is caused by the switching valve 20.The first heat medium having flown into the flow path 128 of the heatstorage unit 190 absorbs the heat from the heat storage material 24.Accordingly, load on the evaporator 18 is reduced, and thus the amountof sticking frost can be reduced. A heater may be provided in theevaporator 18.

In addition, a latent heat storage material capable of supercooling isused as the heat storage material 24 and, when the latent heat storagematerial is in a supercooled state, supercooling is released by thenucleation unit 300 after it has been determined that the temperature ofthe compressor 11 (T_(comp)) is not less than the predetermined lowerlimit (T_(comp) _(—) _(min)) and the temperature of the evaporator 18(T_(ev2)) is lower than the predetermined lower limit (T_(min)).Accordingly, even when the period from storing heat in the heat storagematerial 24 to releasing the heat is long, heat at the melting point canbe released from the heat storage material 24, and thus the first heatmedium can absorb sufficient heat.

In the embodiment, when the temperature of the compressor 11 and thetemperature of the second heat medium are higher than the temperature ofthe heat storage material 24, the heat storage material 24 absorbs heatfrom the compressor 11 and the second heat medium.

In contrast to this, when the temperature of the compressor 11 or thetemperature of the first heat medium is low, the compressor 11 or thefirst heat medium absorbs heat from the heat storage material 24.

Therefore, in an electric vehicle or a fuel-cell vehicle, since heat canbe used more efficiently inside the vehicle, power consumption whenoperating the air conditioning system can be further suppressed.

According to the embodiment illustrated above, an air conditioningsystem capable of reducing power consumption can be realized.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the invention. Moreover, above-mentioned embodiments can becombined mutually and can be carried out.

What is claimed is:
 1. An air conditioning system comprising: a compressor which compresses and discharges a first heat medium taken therein; a condenser provided on a discharge side of the compressor; an expansion valve provided on the outflow side of the condenser; a switching valve which is provided on the outflow side of the expansion valve and which performs switching so that the first heat medium flows through either a first flow path or a second flow path; an evaporator provided downstream of confluence position of the first flow path and the second flow path, on the intake side of the compressor; a pump which supplies a second heat medium to the heat source; a radiator which releases heat of the second heat medium supplied to the heat source; and a heat storage unit having a heat storage material, wherein the heat storage unit has a first heat exchange region in which heat is exchanged between the first heat medium flowing through the first flow path and the heat storage material, and a second heat exchange region which is provided upstream of the radiator and in which heat is exchanged between the second heat medium supplied to the heat source and the heat storage material.
 2. The system according to claim 1, wherein the first flow path connects one outflow side of the switching valve and the evaporator via the heat storage unit, and the second flow path connects the other outflow side of the switching valve and the evaporator.
 3. The system according to claim 1, wherein the second heat exchange region is provided closer to a center of the heat storage unit than the first heat exchange region.
 4. The system according to claim 1, wherein the heat storage unit has a cylindrical shape, the first heat exchange region is provided on a side of an inner wall of the cylindrical heat storage unit, and the second heat exchange region is provided on a side of a center of the cylindrical heat storage unit.
 5. The system according to claim 1 further comprising a first temperature measuring unit which measures temperature of the evaporator, wherein the switching valve performs switching, based on the measured temperature of the evaporator, so that the first heat medium flows through either the first flow path or the second flow path.
 6. The system according to claim 1, wherein the switching valve performs switching so that the first heat medium flows through the second flow path when the measured temperature of the evaporator is higher than a predetermined value, and the switching valve performs switching so that the first heat medium flows through the first flow path when the measured temperature of the evaporator is lower than a predetermined value.
 7. The system according to claim 1, wherein the compressor is thermally connected to the heat storage unit.
 8. The system according to claim 7, further comprising a second temperature measuring unit which measures temperature of the compressor, wherein the switching valve performs switching, based on the measured temperature of the compressor, so that the first heat medium flows through either the first flow path or the second flow path.
 9. The system according to claim 8, wherein the switching valve performs switching so that the first heat medium flows through the second flow path when the measured temperature of the compressor is lower than a predetermined value.
 10. The system according to claim 1, further comprising a nucleation unit which is provided inside the heat storage unit and causes the heat storage material to nucleate.
 11. The system according to claim 1, wherein the heat storage material is a latent heat storage material.
 12. The system according to claim 11, wherein the latent heat storage material includes at least one type selected from the group consisting of sodium acetate hydrate, sodium sulphate hydrate, paraffin, erythritol, and sodium acetate trihydrate.
 13. The system according to claim 9, further comprising a first temperature measuring unit which measures temperature of the evaporator, wherein the heat storage material is a latent heat storage material capable of supercooling, and when the heat storage material is in a supercooled state, and the measured temperature of the evaporator is lower than a predetermined value, the nucleation unit releases the supercooled state of the heat storage material.
 14. The system according to claim 9, wherein the nucleation unit is an electrode which applies a voltage to the heat storage material.
 15. The system according to claim 9, wherein the nucleation unit causes the heat storage material to nucleate at a fixed time interval.
 16. The system according to claim 10, wherein the nucleation unit is provided downward in the gravity direction inside the casing.
 17. The system according to claim 1, further comprising a heating unit which heats the heat storage material.
 18. An air conditioning system comprising: a compressor which compresses and discharges a first heat medium taken therein; a condenser provided on a discharge side of a discharge side of the compressor; an expansion valve provided on the outflow side of the condenser; an evaporator provided on the outflow side of the expansion valve, and also on the intake side of the compressor; a pump which supplies a second heat medium to the heat source; a radiator which releases heat of the second heat medium supplied to the heat source; and a heat storage unit having a heat storage material, wherein the heat storage unit has a first heat exchange region which is provided upstream of the evaporator and in which heat is exchanged between the first heat medium and the heat storage material, and a second heat exchange region which is provided upstream of the radiator and in which heat is exchanged between the second heat medium supplied to the heat source and the heat storage material.
 19. The system according to claim 18, wherein the second heat exchange region is provided closer to the center of the heat storage unit than the first heat exchange region.
 20. The system according to claim 18, wherein the heat second exchange region is provided adjacent to the first heat exchange region. 